Is Fe the Most Active Site for Fe/N-Doped Graphdiyne?

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Pristine graphdiyne (GDY) exhibits limited activity for oxygen reduction reactions (ORRs) due to weak intermediate binding.
• Optimizing catalyst active sites is crucial for efficient ORR catalysis.

Purpose of the Study:

• To systematically investigate the ORR activity of pristine, Fe-doped, N-doped, and Fe/N-codoped GDY.
• To understand the role of doping on the electronic and geometric properties influencing ORR activity.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Analysis of binding energies of reaction intermediates.
• Machine learning analysis of ΔG(OH*).
• Scaling relation analysis and volcano plot construction.

Main Results:

• N-doped GDY shows enhanced ORR activity with a low overpotential of 0.45 V due to improved intermediate binding.
• Fe-doped GDY exhibits an overpotential of 0.43 V, with the most active site located away from Fe.
• Fe/N-codoped GDY shows optimal activity at a C site with an optimal distance from dopants.
• Binding energy of OH* serves as a descriptor for Fe- and/or N-doped GDY activity.

Conclusions:

• The electronic and geometric properties of the active center and its environment significantly impact ORR activity.
• Fe and N doping modulate intermediate binding, with optimally bound C sites being most active.
• Graphdiyne derivatives offer tunable platforms for efficient ORR electrocatalysts.